JPH0365896B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high frequency hybrid integrated circuit.

[Conventional technology]

In circuits that operate at high frequencies, high frequency components are emitted from the line pattern or various used components, often having an adverse effect on other circuits around them.

In order to prevent such interference and to stabilize the entire circuit as a system, it is common practice to cover the high frequency portion with a specially prepared metal plate.

Furthermore, the above-mentioned adverse effects become more pronounced as the frequency and power become higher, and in such areas,
Shielded with a metal plate in close contact with the component.

On the other hand, in recent years, equipment has rapidly become smaller, and as a result, high-frequency hybrid integrated circuits have been forced to become smaller in terms of area and volume, and internal circuits have become increasingly dense. In such highly integrated high frequency circuits, due to the way the metal plate for shielding is grounded, a potential difference occurs between the ground potential on the hybrid integrated circuit and the ground potential of the shield metal plate. There was a problem in that it interacted with the line pattern impedance on the circuit or the constants of the coils, etc., causing changes in the matching conditions of the circuit, and causing oscillation.

A conventional technique for solving the above problem is shown in FIG. In this technology, a circuit board 2 fixed to a metal conductor 1 that serves as the ground is coated over the entire surface with an insulating resin 6 that has low loss at high frequencies, and is also conductive so that it can be electrically connected to the metal conductor 1. The purpose is to shield the circuit by coating or molding a synthetic resin 7.

[Problem that the invention seeks to solve]

As described above, with conventional technology, the entire surface of the circuit board must be coated with a resin that has good insulation and high-frequency characteristics, and then it is necessary to coat or mold a conductive resin on top of that. The disadvantages are that the sealing process is complicated, often requires manual labor, and is expensive.

The present invention has been made to eliminate the above-mentioned drawbacks, and provides a high-frequency hybrid integrated circuit that can simplify the working process, easily shield the high-frequency circuit, and operates stably.

[Means for solving problems]

The device of the present invention applies a metal coating to a plastic cap used in a hybrid integrated circuit, and
The metal film coated on the cap is fixed with a conductive adhesive to a metal conductor that serves as the ground surface.

[Effect]

In this way, the high frequency circuit is covered by the metal film coated on the cap and the metal conductor serving as the ground plane, and the high frequency circuit is electrically shielded from other circuits.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a metal conductor that serves as a ground plane (sometimes serving as a heat sink), 2 is a high-frequency circuit board fixed on the metal conductor 1, 3 is a plastic cap that protects the high-frequency circuit board 2, and 4 is a plastic cap for this. It is a metal coating coated on the inner surface of the plastic cap 3,
5 is a metal conductor 1 serving as a ground plane with the metal coating 4;
It is a conductive adhesive that connects electrically and mechanically.

In the above configuration, the circuit board 2 on which the high frequency circuit is configured includes a metal conductor 1 serving as a ground plane, a metal coating 4 covered with a plastic cap 3,
And, it is completely surrounded by a conductive adhesive 5 for connecting between them, and is electrically shielded from the outside.

As a result, even if, for example, a metal plate is placed in close contact with the hybrid integrated circuit from the outside, the circuit is not affected in any way and can operate stably.

In particular, according to the present invention, great effects can be obtained in high frequency, high power hybrid integrated circuits and filter circuits that handle high power at high frequencies.

〔Effect of the invention〕

As described above, according to the present invention, the high frequency circuit is
There is no need to go through a complicated process such as coating with different types of resin, making it possible to construct a high frequency hybrid integrated circuit at low cost, and also having the effect of accurately shielding the circuit.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the invention. FIG. 2 is a sectional view showing a conventional technique. 1 is a metal conductor serving as a ground plane, 4 is a metal coating fixed to the cap, and 5 is a conductive adhesive.
Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. In a hybrid integrated circuit that is covered with a metal conductor that serves as a ground plane and a plastic cap that protects the circuit, a metal coating is applied to the inner surface or the entire surface of the plastic cap, and the metal coating is insulated from the main parts of the circuit. , a high frequency hybrid integrated circuit characterized in that the metal conductor serving as the ground plane is fixed to the metal conductor with a conductive adhesive.